This study will compare interscalene nerve block versus liposomal bupivacaine (Exparel) for pain control after total shoulder replacements. Each method will be assessed in terms of post operative pain scores, pain medication consumption, length of stay, complications (nerve injuries, hematomas, cardiac/respiratory events) and rate of readmission due to pain. The aims of this study will be achieved through a randomized controlled trial and cost-effectiveness analysis.